Filler assembly for cable gland

ABSTRACT

A dispenser apparatus for a curable liquid material is disclosed. The apparatus comprises a flexible bag defining a first compartment for accommodating a first component of a curable liquid material, and a second compartment for accommodating a second component of the curable liquid material and adapted to communicate with the first chamber to enable mixing of the first and second components to initiate curing of the curable liquid material. A first clamp temporarily prevents mixing of the first and second components, and an elongate nozzle communicates with the second compartment to dispense the mixed curable liquid material therefrom. A second clamp temporarily prevents passage of the curable liquid material from the second compartment to the nozzle.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/391,539 filed May 2, 2012, which claims priority to PCT InternationalApplication No. PCT/GB2010/050989 filed on Jun. 14, 2010, which claimspriority to European Patent Application No. 09168430.8 filed on Aug. 21,2009, European Patent Application No. 09168429.0 filed on Aug. 21, 2009,Great Britain Patent Application 1004216.6 filed on Mar. 15, 2010 andGreat Britain Patent Application 1009450.6 filed on Jun. 7, 2010, all ofwhich are fully incorporated by reference herein.

STATEMENT CONCERNING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

FIELD OF THE INVENTION

The present invention relates to a filler assembly for cable glands andrelates particularly, but not exclusively, to such a filler assembly forfilling cable glands for use in hazardous areas.

BACKGROUND OF THE INVENTION

Many cable glands for use in connecting a cable to an enclosure inhazardous areas need to be filled with a compound which provides abarrier against the effects of an explosion occurring within theenclosure to which the cable gland is attached. The barrier is typicallyformed from a two-part clay-filled epoxy compound. The two componentparts of the compound need to be thoroughly mixed with each other priorto fitting into the gland, and the resulting putty like material needsto be packed between the individual conductors in the cable. Such anarrangement is disclosed in GB 2258350.

This known arrangement suffers from a number of drawbacks. Firstly, thecure time of the putty like material is chosen to be relatively long, inorder to enable it to be manipulated into the spaces between theindividual conductors before curing becomes advanced. As a result, thefilled cable assembly must be left undisturbed for a significant period,usually several hours, especially if mixed at low temperatures. Also,the components of the filler material sometimes contain hazardousmaterials which become harmless when the filler material is mixed.Persons mixing the components of the putty like filler material may comeinto contact with these hazardous materials during mixing, and air canbecome trapped within the cable gland by the filler material which maycause the barrier formed by the filler material to fail in the event ofan explosion. Filling of the cable gland is also relatively difficult,especially in the case of small cable glands.

GB 765082 discloses an arrangement for insulating a splice between twostranded connectors in which resinous material is introduced from acapsule having an elongate tip. However, this arrangement suffers fromthe drawback that it is not suitable for filling cable glands, since theintroduction of a material which is sufficiently fluid to penetratebetween the individual conductors of a cable would cause material toflow along the conductors along the interior of the cable, which wouldprevent the cable gland from being sufficiently filled to expel all ofthe air from the cable gland to avoid air voids.

Preferred embodiments of the present invention seek to overcome one ormore of the above disadvantages of the prior art.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, there is provided afiller assembly for filling a cable gland, having a plurality of coresof at least one cable extending therethrough, with curable liquidmaterial, the assembly comprising:

(a) a dispenser apparatus for a curable liquid material, the apparatuscomprising:

a body adapted to define at least one first chamber for accommodating afirst component of a curable liquid material, and at least one secondchamber for accommodating a second component of said curable liquidmaterial, wherein mixing of said first and second components initiatescuring of said curable liquid material; and

at least one elongate dispenser device adapted to dispense said mixedcurable liquid material therefrom between a plurality of cores of atleast one cable; and

(b) at least one flexible barrier member having at least one respectiveaperture therethrough and adapted to engage a plurality of cores of acable to provide a barrier to passage of said curable liquid materialalong said cores.

As a result of the provision of at least one elongate dispenser device,dispensing of the curable liquid can be more carefully controlled, as aresult of which less viscous and faster curing liquid material can beused than in the prior art. This therefore provides the advantage ofenabling more rapid formation of a filled cable gland incorporating thematerial, while also allowing the liquid material to be introduced intothe cable gland in such a way that the air is expelled from the cablegland to avoid air voids, which could lead to failure of the cable glandin the event of an explosion. In addition, with the present invention,the curable material can be dispensed into the assembled gland, i.e. thecable gland can be filled with the conductors of the cable in aconnected state, as a result of which the electrical integrity of thejoint can be ensured, whereas the putty like compound of the knownarrangement must be molded around the conductors of the cable with thegland disassembled, as a result of which the cable cores can not beelectrically connected. The provision of at least one barrier member forrestricting the extent of penetration of said curable liquid materialalong the cable cores provides the advantage of enabling highly flowablecurable liquid material to be used, while also enabling filling of thecable gland.

The body may be flexible.

This provides the advantage of making the apparatus easier and lessexpensive to manufacture.

The assembly may further comprise a first component of a curable liquidmaterial in at least one said first chamber, and a second component ofsaid curable liquid material in at least one said second chamber.

The curable liquid material may be adapted to change colour as a resultof curing thereof.

This provides the advantage of providing a visual indicator to the userwhen the cable gland filling process is complete.

The assembly may further comprise a cover member for covering anexternal screw thread of a cable gland to prevent said curable liquidmaterial coming into contact with said screw thread.

The cover member may be adapted to prevent curable liquid material frompenetrating an end face of the cable gland.

At least one said barrier member may comprise a respective flexiblemember having at least one aperture therethrough for engaging at leastone core of at least one cable.

At least one said barrier member may have a respective tapering portion.

According to another aspect of the present invention, there is provideda method of filling a cable gland with curable liquid material, themethod comprising:

using a filler assembly that includes:

(a) a dispenser apparatus for a curable liquid material, the apparatuscomprising:

a body adapted to define at least one first chamber for accommodating afirst component of a curable liquid material, and at least one secondchamber for accommodating a second component of said curable liquidmaterial, wherein mixing of said first and second components initiatescuring of said curable liquid material; and

at least one elongate dispenser device adapted to dispense said mixedcurable liquid material therefrom between a plurality of cores of atleast one cable; and

(b) at least one flexible barrier member for having at least onerespective aperture therethrough and adapted to engage a plurality ofcores of a cable to provide a barrier to passage of said curable liquidmaterial along said cores;

locating at least one said barrier member in the cable gland; and

locating an outlet of at least one said dispenser device in said cablegland and dispensing curable liquid material therefrom so as to expelair from the cable gland.

The step of locating at least one said barrier member in the cable glandmay comprise locating at least one said barrier member around at leastone said core of at least one said cable.

The assembly may further comprise at least one barrier apparatus fortemporarily preventing passage of the curable liquid material from theor each second chamber to at least one dispenser device. In addition,the barrier apparatus may comprise at least one releasable clamp.

According to another aspect of the invention, there is provided a cablegland for receiving a plurality of cores of at least one cable, thecable gland comprising:

(a) a body adapted to have a plurality of cores of at least one cableextend therethrough;

(b) a dispenser apparatus for a curable liquid material, the apparatuscomprising:

a body adapted to define at least one first chamber for accommodating afirst component of a curable liquid material, and at least one secondchamber for accommodating a second component of said curable liquidmaterial, wherein mixing of said first and second components initiatescuring of said curable liquid material; and

at least one elongate dispenser device adapted to dispense said mixedcurable liquid material therefrom between a plurality of cores of atleast one cable; and

(c) at least one flexible barrier member having at least one respectiveaperture therethrough and adapted to engage a plurality of cores of acable to provide a barrier to passage of said curable liquid materialalong said cores.

The elongate dispenser device may be sufficiently stiff to be insertedbetween the cores of the cable in the vicinity of the flexible barriermember.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the invention will now be described, by way ofexample only and not in any limitative sense, with reference to theaccompanying drawings in which:

FIG. 1 is a perspective view of a dispensing apparatus embodying thepresent invention;

FIG. 2 is a partially cut away perspective view of a cable gland havinga filler formed using the apparatus of FIG. 1; and

FIG. 3 is a cross sectional view of the filled cable gland of FIG. 2with a thread protector in place.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A preferred embodiment of the invention will now be described, by way ofexample only and not in any limitative sense, with reference to theaccompanying drawings in which:

FIG. 1 is a perspective view of a dispensing apparatus embodying thepresent invention;

FIG. 2 is a partially cut away perspective view of a cable gland havinga filler formed using the apparatus of FIG. 1; and

FIG. 3 is a cross sectional view of the filled cable gland of FIG. 2with a thread protector in place.

Referring to FIG. 1, a dispenser apparatus 2 embodying the presentinvention and for use in filling a cable gland 4 (FIG. 2) with curableliquid material 6 comprises a body of suitable transparent flexibleplastics material defining a flexible bag 8 having a first compartment10 for accommodating a first component of a liquid curable material 6,and a second compartment 12 for accommodating a second component of thematerial 6. A first clamp 14 temporarily separates the first compartment10 and second compartment 12 to thereby prevent mixing of the first andsecond components of the material 6. The first and second components arecoloured differently (for example blue and yellow) so that thoroughmixing of the first and second components produces a green liquid,thereby providing a visual indication when thorough mixing of the firstand second components has occurred. Mixing of the first and secondcomponents together causes gelling of the material and initiates curingof the curable liquid material 6.

The dispenser apparatus 2 is also provided with an elongate hollownozzle 16 extending from the second compartment 12 such that dispensingof the mixed curable liquid material can be carefully controlled. Inparticular, the nozzle 16 can be inserted a considerable distance intothe cable gland 4 and between individual core conductors 20 of the coreof a cable 22 attached to the cable gland 4 (FIG. 2) so that the liquidmaterial 6 can be highly flowable and fast-curing, as a result of whichthe cable gland 4 can be rapidly filled and air entrapment by the liquidmaterial 6 minimised. A second clamp 18 temporarily prevents materialflowing from the second compartment 12 into the nozzle 16, so thatdispensing of the material 6 can be prevented until thorough mixingtogether of the first and second components has occurred.

The flexible bag 8 is formed from two sheets of material welded togetheralong all but one of their edges to form a bag having an open mouth,which is then mounted to the nozzle 16. The second clamp 18 is thenmounted to the bag adjacent to the nozzle 16, and the second componentof the material 6 is dispensed into the second compartment 12. The firstclamp 14 is then mounted to the bag to seal the second component in thesecond compartment 12, and the first component is then dispensed intothe first compartment 10. The open edge of the bag is then sealed toseal the first component in the first compartment 10.

Referring to FIGS. 2 and 3, the cable gland 4 to be filled by means ofthe dispenser apparatus 2 of FIG. 1 comprises a threaded outer connector24 for threaded connection to an enclosure (not shown) and a compoundtube 26 rotatably mounted within the outer connector 24. A cableconnector 28 is mounted to the end of the cable 22 and is connected tothe outer connector 24 by means of cooperating screw threads (notshown).

A ring 30 abuts the cable connector 28 and a flexible seal 32 is locatedaround the core conductors 20 of the cable 22 and compressed between thecompound tube 26 and ring 30 for limiting the extent of penetration ofcurable material 6 into the cable gland 4 before curing of the curablematerial 6. The flexible seal 32 comprises a generally frusto-conicalbody of elastomeric material having an aperture (not shown) therethroughfor engaging the core conductors 20 of the cable 22. The aperture in theseal 32 is sized such that it stretches to pass around the coreconductors 20 to tightly engage the core conductors 20 to form areasonably effective barrier to passage of the material 6 along thespace defined between the core conductors 20 and the compound tube 26.

Referring to FIG. 3, a thread protector 34 formed of elastomericmaterial such as rubber is located over the external screw thread of theouter connector 24 of the cable gland 4 prior to filling of the cablegland with curable material 6. The thread protector 34 has a hollow rim36 for catching excess curable material 6 which may flow out of end 40of the cable gland 4 during the filling procedure, and an inner circularrim 38 which prevents penetration of curable material 6 into the gapbetween the outer connector 24 and the compound tube 26. This ensuresthat the compound tube 26 complete with cable connectors 28 can beremoved from the outer connector 24 after curing of the material 6.

The process of filling the cable gland 4 of FIGS. 2 and 3 by means ofthe dispenser apparatus 2 of FIG. 1 will now be described.

In order to fill the core of the cable gland 4 with curable material,the flexible seal 32 initially placed over the core conductors 20 of thecable 22 so that the seal 32 tightly grips the core conductors 20. Theouter connector 24 with compound tube 26 are then mounted to the ring 30and cable connector 28 to compress the seal 32 between the ring 30 andcompound tube 26. As a result, the flexible seal 32 acts as a barrier topenetration of the curable liquid material 6 into the interior of thecable gland 4.

The first clamp 14 is then removed from the dispenser apparatus 2 andthe second clamp 18 left in place, to enable thorough mixing of thefirst and second components of the curable liquid material 6. The firstand second components are coloured blue and yellow respectively, aresult of which the curable liquid material 6 is bright green when it isthoroughly mixed. The second clamp 18 is then removed, and the outlet ofthe nozzle 16 is placed at a location near the seal 32. The liquidmaterial 6 is then dispensed through the nozzle 16 into the spacebetween the core conductors 20 of the cable 22 and into the space aroundthe core conductors 20 inside the compound tube 26 of the cable gland 4,where its movement along the axis of the cable gland 4 is restricted bythe flexible seal 32. The location of the outlet of the nozzle 16 nearthe seal 32 causes air to be expelled from the cable gland when thecurable liquid material 6 is dispensed from the nozzle 16. The seal 32provides a sufficient barrier to penetration of the material 6 to holdback the curable material until it begins to gel and support itself. Atthe same time, the thread protector 34 protects the external thread ofthe outer connector 24 from excess curable material and preventspenetration of the liquid curable material between the outer connector24 and the compound tube 26. The material 6 is arranged to change colourto dark green when it is cured, so that a visual indication is providedwhen the curing process is completed.

It will be appreciated by persons skilled in the art that the aboveembodiment has been described by way of example only, and not in anylimitative sense, and that various alterations and modifications arepossible without departure from the scope of the invention as defined bythe appended claims.

1. A filler assembly for filling a cable gland with curable liquidmaterial, the assembly comprising: (a) a dispenser apparatus for acurable liquid material, the apparatus comprising: a body defining atleast one first chamber accommodating a first component of a curableliquid material, and at least one second chamber accommodating a secondcomponent of said curable liquid material, wherein mixing of said firstand second components initiates curing of said curable liquid material;and at least one dispenser device adapted to dispense said mixed curableliquid material therefrom between a plurality of said cores of saidcable; and (b) at least one flexible barrier member having at least onerespective aperture therethrough and adapted to stretch to engage aplurality of cores of a cable to provide a barrier to passage of saidcurable liquid material along said cores.
 2. An assembly according toclaim 1, wherein said body is sufficiently flexible to enablemanipulation of said curable liquid material through said body.
 3. Anassembly according to claim 1, further comprising at least one firstbarrier apparatus for temporarily preventing mixing of said first andsecond components.
 4. An assembly according to claim 3, wherein at leastone said first barrier apparatus comprises at least one releasableclamp.
 5. An assembly according to claim 1, wherein the curable liquidmaterial is adapted to change color as a result of curing thereof.
 6. Anassembly according to claim 1, further comprising a cover member forcovering an external screw thread of a cable gland to prevent saidcurable liquid material coming into contact with said screw thread. 7.An assembly according to claim 6, wherein the cover member is adapted toprevent curable liquid material from penetrating an end face of thecable gland.
 8. An assembly according to claim 1, wherein at least onesaid barrier member has a respective tapering portion.
 9. A method offilling a cable gland, having a plurality of cores of a cable extendingtherethrough, with curable liquid material, the method comprising: usinga filler assembly that includes: (a) a dispenser apparatus for a curableliquid material, the apparatus comprising:— a body defining at least onefirst chamber accommodating a first component of a curable liquidmaterial, and at least one second chamber accommodating a secondcomponent of said curable liquid material, wherein mixing of said firstand second components initiates curing of said curable liquid material;and at least one dispenser device adapted to dispense said mixed curableliquid material therefrom between a plurality of said cores of saidcable; and (b) at least one flexible barrier member for having at leastone respective aperture therethrough and adapted to stretch to engage aplurality of said cores of said cable to provide a barrier to passage ofsaid curable liquid material along said cores; locating at least onesaid barrier member in the cable gland; and locating an outlet of saiddispenser device in said cable gland and dispensing curable liquidmaterial therefrom so as to expel air from the cable gland.
 10. A methodaccording to claim 9, wherein the step of locating at least one saidbarrier member in the cable gland comprises locating said barrier memberaround a plurality of said cores of said cable.
 11. An assemblyaccording to claim 1, further comprising at least one second barrierapparatus for temporarily preventing passage of said curable liquidmaterial from said second chamber to at least one said dispenser device.12. An assembly according to claim 11, wherein at least one said secondbarrier apparatus comprises at least one releasable clamp.
 13. A cablegland assembly comprising: (a) a body; (b) a dispenser apparatus for acurable liquid material, the apparatus comprising: a body defining atleast one first chamber accommodating a first component of a curableliquid material, and at least one second chamber accommodating a secondcomponent of said curable liquid material, wherein mixing of said firstand second components initiates curing of said curable liquid material;and at least one dispenser device adapted to dispense said mixed curableliquid material therefrom between a plurality of cores of a cable; and(c) at least one flexible barrier member having at least one respectiveaperture therethrough and adapted to stretch to engage a plurality ofsaid cores of said cable to provide a barrier to passage of said curableliquid material along said cores.
 14. An assembly according to claim 1,wherein at least one said dispenser device is sufficiently stiff to beinserted between the cores of the cable in the vicinity of the flexiblebarrier member.
 15. A filler assembly according to claim 1, wherein thebarrier member is sufficiently flexible and the curable liquid materialis sufficiently liquid that the barrier member is adapted to stretch toengage a plurality of cores of a cable to provide a barrier to passageof said curable liquid material along and between said cores beyond thebarrier member.